Schindler 3300 / Schindler 5300 Information on noise and vibration.

Schindler 3300 / Schindler 5300
Information on noise and vibration.
Content
Introduction
1. Ride quality
Jerk
Car acceleration
Vertical car vibration
Lateral car vibration
Sound in the car
2. Sound – basics
3.Vibration – basics
4.Structure-borne noise
Introduction
This document is intended to give an introduction to noise and vibration
aspects for the Schindler 3300 and Schindler 5300 elevator systems.
It gives a short overview of the basics of noise and vibration and specifies
the values that customers can expect for these systems.
Noise and vibration aspects for an elevator system cover the following
areas:
– Ride quality: sound and vibration inside the car
– Air-borne noise, e.g. door noise, noise in the elevator shaft
– Structure-borne noise in walls: important, as it radiates sound into
adjacent rooms
The basics of these aspects will be presented in chapters 2 to 4.
During operation of an elevator, the following types of noise are present:
– Cooling fan noise (drive and frequency converter)
– Drive operation noise
– Relay switching noise (impulse noise)
– Door noise
– Guide shoe sliding noise (only during a short phase after installation)
Not every type of noise is equally disturbing. This strongly depends
on the nature of the noise, relative background noise and on psychological aspects. Please note that noise is defined as unwanted sound,
i.e. sound at the wrong place at the wrong time.
Schindler Passenger Elevators
1. Ride quality.
Ride quality is the term that stands for the following set of aspects:
– Jerk
– Car acceleration
– Vertical car vibration
– Lateral car vibration
– Sound inside the car
1.1Jerk
Jerk, unit: m/s3, is the time-derivative of acceleration. If the elevator moves with
high jerk, acceleration changes are very abrupt and can be felt as bumps.
1.2Car acceleration
Car acceleration, unit: m/s2, determines how long it takes before the car reaches
its maximum speed. A high acceleration is generally considered uncomfortable,
however, it gives the impression that the car moves very fast.
1.3Vertical car vibration
Vibration is also measured as acceleration, unit: m/s2. This kind of vibration can
be felt by the feet of a person, but is also discerned by the stomach and the
internal ear. It is mostly caused by vibrations of the drive and frequency converter. These are transferred to the car by the traction media.
1.4Lateral car vibration
Lateral car vibration is caused by non-straightness of the guide rails, play
between car and guide rails and non-smooth guide rail transitions. Generally,
it causes low-frequent lateral movements of the car.
1.5Sound in the car
Generally, sound levels in elevators should be low enough not to interfere
with speech, but hearing the elevator in motion is desirable from a
psychological point of view.
2
Information on noise and vibration
Noise and vibration performance
Adjacent rooms1
LpAmax
30 dB(A) incl. impulse
noise
Shaft2
LpAeq
LpAmax
62 dB(A)
65 dB(A) impulse noise
Structure-borne noise3
Octave
[Hz]
63
125
250
500
Lamax
[dB]
90
90
85
85
Landing
Door noise4
60 dB(A)
LpAmax
Pass-by noise
LpAmax
50 dB(A)
Impulse noise at top floor
LpAmax
55 dB(A)
Car
Sound pressure level
LpAeq
50 ±3 dB(A)
57 dB(A) impulse noise
LpAmax
Vibrations (ride quality)
Lateral
– ISO MPtP < 15 mg
– ISO A95
< 10 ±3 mg
Vertical
– ISO MPtP
– ISO A95
< 25 mg
< 15 ±5 mg
1
VDI 2566-2:2004 prescribes a maximum permissible A-weighted sound level LpAmax in adjacent rooms of 30 dB(A). It is the responsibility of the architect /
building designer to ensure that the walls and roof of the shaft provide enough air-borne and structure-borne noise attenuation. The main parameter is
the area-specific mass of the hoistway wall. Table 2 of VDI 2566-2:2004 provides rules for the design of the walls depending on the room configuration.
These rules are based on standard DIN 4109 supplement 1a.
2
VDI 2566-2:2004 specifies a maximum sound pressure level in the hoistway of 75 dB(A).
3
The levels listed are the levels according to VDI 2566-2:2004. The Schindler 3300 and Schindler 5300 elevator systems generally fulfill these levels with
a large margin, depending on the type of wall.
4
VDI 2566-2:2004 specifies a maximum A-weighted sound pressure level for door noise of 65 dB(A).
Information on noise and vibration
3
Definitions
LpAeq
LpAmax
Sound
A-weighted equivalent sound pressure level: the steady sound level that, over a specified period of time, would produce the
same energy equivalence as the fluctuating sound level actually
occurring. (Can be interpreted as a mean level and measured
directly with an integrating sound level meter.)
Maximum A-weighted sound pressure level
All sound pressure level measurements require setting «FAST»
of the sound level meter.
Vibration / structure-borne noise
Lamax
ISO MPtP
ISO A95
Maximum acceleration level [dB] lin re: 1·10-6 m/s2
ISO-weighted Maximum Peak-to-Peak vibration value, according
to ISO 18738:2003
ISO-weighted A95 vibration value according to ISO 18738:2003.
95% of all peaks of the ISO-weighted signal are below this value.
Applicable standards
VDI 2566-2:2004
Acoustical design for lifts without machine room
ISO 2631-1:1997
Mechanical vibration and shock – Evaluation of human exposure
to whole-body vibration – Part 1: General requirements
ISO 18738:2003
Lifts (elevators) – Measurements of lift ride quality
ISO 8041:1990 and Amd.1:1999
4
Information on noise and vibration
Human response to vibration – Measuring instrumentation
2. Sound – basics.
Sound is an air pressure variation that is sensed by the ears. An example
of sound generating equipment is a loudspeaker. The movement of the
loudspeaker membrane causes a varying rarefaction and compression of
the air in front of it.
p0 + p(t) [Pa]
compression zones
p0
p0
0
p0 + p(t)
t[s]
rarefaction zones
Figure 2.1
The speed with which the rarefied and compressed zones travel away
from the speaker is the sound speed c. At room temperature
20 °C, c = 344 m/s.
The pressure variation p(t) is added to the local atmospheric pressure p0.
It is only this pressure variation that is heard by the ear.
To accommodate the large range of human hearing, the sound pressure level
(SPL) is defined:
Lp : = 20∙log
p
p0
where:
Lp Sound pressure level [dB]
p Instantaneous sound pressure [Pa]
p0 Reference pressure, equals 20_Pa (threshold of hearing)
Normally, the sound pressure level is A-weighted, see figure 2.2.
An A-weighted sound pressure level is designated with dB(A).
A-weighting is widely considered the best weighting to represent
human hearing. Low-frequency components are strongly attenuated
by this type of frequency weighting.
Information on noise and vibration
5
Figure 2.2
A-weighting curve
Correction [dB]
10
0
–10
–20
–30
–40
–50
– 60
–70
– 80
101
102
103
104
f [Hz]
Examples of different A-weighted sound pressure levels are shown
in table 2.1.
Table 2.1
6
Information on noise and vibration
Phenomenon
SPL [dB(A)]
Jet taking off, 25 meters, threshold of pain
140
Live concert
120
Heavy truck at small distance
100
Noisy office
80
Conversational speech, 1 m
60
Room at home
40
Whisper, leaves rustling
20
Threshold of hearing
0
3. Vibration – basics.
a
a
[m/s2] [mg]
0.01
1.02
0.1
10.2
1
102
Within the elevator industry, the recognized unit for vibration is milli-g
(mg). One mg equals ca. 0.01 m/s2. Values in mg and m/s2 can be easily
converted using table 3.1.
Subjective vibration perception
The way people «feel» vibrations depends strongly on the vibration direction.
One has to distinguish between vertical vibration and horizontal vibration, the
latter often called lateral vibration. The difference in perception is resembled
by the ISO-filter that is described in ISO 8041 Amd.1:1999. The filter weighting
curves for horizontal and vertical vibrations are shown in figures 3.1 and 3.2.
Table 3.1
The threshold of vibration perception is
about 2–3 mg for vertical vibrations.
Figure 3.1
Filter weighting curve for horizontal
vibrations according to ISO 8041
Amd. 1:1999
Weighting, dB
0
–10
–20
–30
–40
–50
– 60
–70
– 80
0,1 0,16 0,25 0,4 0,63
1 1,6 2,5
4 6,3
10 16
25
40
63 100 160 250 400
Frequency, Hz
Figure 4.2
Filter weighting curve for vertical
vibrations according to ISO 8041
Amd.1:1999
From the weighting curves it can be
seen that humans are most sensitive for
horizontal vibrations in the frequency
range 0.5–2 Hz. For vertical vibrations,
this range is 5–12 Hz.
Weighting, dB
0
–10
–20
–30
–40
–50
– 60
–70
– 80
0,1 0,16 0,25 0,4 0,63
1 1,6 2,5
4 6,3
10 16
25
40
63 100 160 250 400
Frequency, Hz
Information on noise and vibration
7
4. Structure-borne noise.
Above 20 Hz, vibration may be called structure-borne noise. Such
vibrations may generate audible sound. Generally, structure-borne noise
can be considered important for frequencies below 1000 Hz.
Standard VDI 2566-2:2004, «Acoustical design for lifts without machine
room», presents a guideline for the amount of structure-borne noise that
may be present in a hoistway wall of an elevator. The purpose of this
guideline is to minimize perception of elevator noise in adjacent rooms
according to international standards.
Whereas vibrations have unit m/s2 or mg, structure-borne noise is
measured in dB because of its strong relation with airborne noise.
La : = 20∙log a
a0
where:
La Vibration level [dB]
a Instantaneous acceleration [m/s2]
a0Reference acceleration according to ISO, a0 = 1·10-6 m/s2
The maximum permissible values are listed in table 4.1.
Octave band La,max
mid-frequency
[Hz]
[dB] lin re: 1E-6m/s2
63
90
125
90
250
85
500
85
GB-COMM.noise&vib.EN.05.08
Table 4.1
www.schindler.com
These levels do not automatically guarantee that the sound pressure
level in adjacent rooms will not exceed 30 dB(A). The walls need
to have a specific mass such that this requirement can be fulfilled.
Architects and building contractors have the responsibility to assure
that the building interface is designed appropriately.